A new method for determining surface roughness based on improving the kinematics of the milling cutter movement during micro-cutting has the advantage of the precise spatial position of the micro cutter edge. A change in the components of the speed of movement and rotation during a complex movement of the cutter changes the mechanism of plunging of the cutting edge into the workpiece material. Based on the model developed in this work, the kinematic parameters of the cutter were determined, and new relationships between the cutter geometry and parameters of the technological process were discovered. The revealed new relationships made it possible to determine not only the mechanism of chip formation but also the dimensions of damages to the workpiece surface during plunger cutting. © 2021 SPIE